I look happy most of the time to hide my rage

I've pretty much always gotten in trouble for being upset whenever I've been unhappy/disappointed/etc around my family so I learned to hide my emotions, especially the anger. I've still lost my cool sometimes but for the most part, I have to keep it inside. But I'm so full of anger and bitterness and resentment from all my life that it's getting harder and harder to keep and hide it in. And because I have all this anger and sadness that's turned inward I hate myself.

Tonight I was tired and upset and although the first few times I said I was ok, a family member kept pressing and I eventually told the truth and said I was tired and resentful of how that older family member was acting. Big mistake, and the argument ended with it being my fault like always. When I got home I wanted to throw up dinner to punish myself for falling for it again and because it's one of the only things I have left that is in my control. I am told how to act and my opinion never matters, even with things that directly concern me.

The problem is, I can't throw up anymore. I tried shoving a toothbrush and then one, two, three fingers, but I seem to have lost my gag reflex. I still retch but nothing came out but spit and some blood, a sore throat afterward. I punched myself in the gut several times but all I got were bruises. This really upsets me because this means I'm now losing one of the few things I could control and I'm afraid this is going to lead to something more serious.